down()

static void down ( MINHEAP *  tree, areanode *  arealist, int  parent  )

static

Sift Down.

Definition at line 123 of file effectivearea.c.

References areanode::area, MINHEAP::key_array, LWDEBUG, and areanode::treeindex.

Referenced by minheap_pop(), and minheap_update().

{
        LWDEBUG(2, "Entered  down");
        areanode **treearray=tree->key_array;
        int left=parent*2+1;
        int right = left +1;
        void *tmp;
        int swap=parent;
        double leftarea=0;
        double rightarea=0;

        double parentarea=((areanode*) treearray[parent])->area;

        if(left<tree->usedSize)
        {
                leftarea=((areanode*) treearray[left])->area;
                if(parentarea>leftarea)
                        swap=left;
        }
        if(right<tree->usedSize)
        {
                rightarea=((areanode*) treearray[right])->area;
                if(rightarea<parentarea&&rightarea<leftarea)
                        swap=right;
        }
        if(swap>parent)
        {
        /*ok, we have to swap something*/
                tmp=treearray[parent];
                treearray[parent]=treearray[swap];
                /*Update reference*/
                ((areanode*) treearray[parent])->treeindex=parent;
                treearray[swap]=tmp;
                /*Update reference*/
                ((areanode*) treearray[swap])->treeindex=swap;
                if(swap<tree->usedSize)
                        down(tree,arealist,swap);
        }
        return;
}

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